The role of land use and soils in regulating water flow in small headwater catchments of the Andes

Abstract

[1] Land use changes can have a significant impact on the terrestrial component of the water cycle. This study provides a comparison of three small headwater catchments in the Andean mountains of Colombia with different composition of land use. Several methods were used to quantify differences in the hydrological behavior of these catchments such as flow duration curves, stormflow analysis, and the linear reservoir concept. They were combined with an analysis of the characteristics of soils that contribute to understanding the aggregate catchment hydrological behavior. Andisols, which are soils formed in volcanic areas and with a large capacity to hold water, amplify differences in land use and limit the potential impact of land use management activities (conservation or restoration) on the water regulation function of catchments. Of the three studied catchments, less variability of flows was observed from the catchment with a larger percentage of area in forest, and a slower decrease of flows in the dry season was observed for the catchment with a relatively higher percentage of area in wetlands. Evidence is provided for the infiltration trade-off hypothesis for tropical environments, which states that after forest removal, soil infiltration rates are smaller and the water losses through quick flow are larger than the gains by reduced evapotranspiration; this is compatible with the results of the application of the linear reservoir concept showing a faster release of water for the least forested catchment.

Índice de qualidade do solo associado à recarga de água subterrânea (IQS RA) na Bacia Hidrográfica do Alto Rio Grande, MG

“…No âmbito da região da Serra da Mantiqueira, Menezes et al (2009) Esses resultados encontram sustentação em trabalhos recentes, como os de Bonell et al (2010), Roa-Garcia et al (2011) e Hümann et al (2011, os quais estudaram o comportamento da condutividade hidráulica sob condições de Floresta Nativa nos Andes colombianos, no sudoeste da Alemanha e no oeste da Índia, respectivamente. Nesses trabalhos, ficou constatado que a presença de florestas nativas, em avançado estádio de desenvolvimento (floresta madura), propicia condições para a gênese de poros gravitacionais com altos valores de porosidade drenável e condutividade hidráulica saturada, com a formação de fluxos preferenciais.…”

“…Entretanto, esses índices não captam a influência do uso do solo nos atributos de superfície associados à infiltração de água, o que, em condições tropicais e subtropicais, são mais relevantes do que indicadores baseados apenas da paisagem. Um exemplo fundamental dessa situação consiste da influência de matas nativas no comportamento hidrológico de bacias hidrográficas de cabeceira (Bonell et al, 2010;Roa-Garcia et al, 2011). Nessa linha, Menezes et al (2009) buscaram analisar o comportamento hidrológico de duas nascentes em função das características pedológicas do Cambissolo na região da Serra da Mantiqueira.…”

Importance of vegetation, topography and flow paths for water transit times of base flow in alpine headwater catchments

“…The authors found higher rates of stream discharge during precipitation events in the catchment with a higher percentage of grazed grassland, which is explained by compaction of soils. On the long time scale they found differences in the MTTs, which they ascribe to the difference in vegetation cover/land use, notably the occurrence of wetlands and forests which increased MTTs due to an increased water holding capacity (Roa-Garcia, 2009). Darling and Bath (1988) measured more negative δ 18 O values in the percolate of a lysimeter compared to soil water samples of drill cores from the same depth.…”

Quantification of runoff generation from a combined glacier and <i>páramo</i> catchment within an Ecological Reserve in the Ecuadorian highlands

“…Soils are mainly andosols, based on the FAO classification (Gardi et al, 2014), derived from volcanic material characterized by their high soil moisture (Buytaert et al, 2005a) and water retention capacity (Janeau et al, 2015;Roa-García et al, 2011). In 45 addition, studies in the area describe an elevated amount of organic carbon and mineralogical composition in the soil of the páramos at lower catchments, which decreases with altitudinal gradient (Minaya et al, 2015).…”